Date: Tue, 22 Aug 2017 08:17:38 -0700 From: David Wolfskill <david@catwhisker.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: current@freebsd.org Subject: Re: SIGSEGV in /bin/sh after r322740 -> r322776 update Message-ID: <20170822151738.GV1130@albert.catwhisker.org> In-Reply-To: <20170822131958.GE1700@kib.kiev.ua> References: <20170822114627.GC1130@albert.catwhisker.org> <20170822115923.GC1700@kib.kiev.ua> <20170822122836.GH1130@albert.catwhisker.org> <20170822123449.GD1700@kib.kiev.ua> <20170822124617.GN1130@albert.catwhisker.org> <20170822131958.GE1700@kib.kiev.ua>
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On Tue, Aug 22, 2017 at 04:19:58PM +0300, Konstantin Belousov wrote:
> ...
> > > Ok, can you rebuild kernel and libc from scratch ? I.e. remove your
> > > object directories.
> >=20
> > I think I'll need a working /bin/sh to do that. As noted, I could
> > try the stable/11 /bin/sh; on the other hand, if it's dying in a
> > library, that's not likely to help a whole lot. :-}
> I highly suspect that this is not /bin/sh at all. Backtrace strongly
> suggests that the malloc() has issues, but again I suspect that the
> reason is not an issue in malloc, but its use of TLS.
>=20
> The amd64 changes were to the TLS base register handling. So you might
> try to boot previous kernel. If this works out without replacing libc
> then it is definitely TLS, but I still do not know what is wrong.
>=20
> >=20
> > But yes: once we resolve the "working /bin/sh" issue, clearing
> > /usr/obj & rebuilding is straighforward and shouldn't take too long.
> ....
OK. Booting from the previous kernel (/boot/kernel.old) allowed /bin/sh
(et al.) to work without segfaults, so after clearing /usr/obj, I
rebuilt r322776 from scratch (yes, userland as well as kernel).
On reboot, I wtached the serial console, and noted:
=2E..
Mounting local filesystems:.
ELF ldconfig path: /lib /usr/lib /usr/lib/compat /usr/local/lib /usr/local/=
lib/perl5/5.24/mach/CORE
32-bit compatibility ldconfig path: /usr/lib32 /usr/lib32/compat
Setting hostname: freebeast.catwhisker.org.
Setting up harvesting: [UMA],[FS_ATIME],SWI,INTERRUPT,NET_NG,NET_ETHER,NET_=
TUN,MOUSE,KEYBOARD,ATTACH,CACHED
Feeding entropy: .
Starting Network: lo0 re0.
lo0: flags=3D8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
options=3D600003<RXCSUM,TXCSUM,RXCSUM_IPV6,TXCSUM_pIPV6>
inet6 ::id 298 (sh), uid 0: exited on signal 11 prefixlen 128 1 (co=
re dumped)
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x2=20
inet 127.0.0.1 netmask 0xff000000=20
nd6 options=3D21<PERFORMNUD,AUTO_LINKLOCAL>
groups: lo=20
re0: flags=3D8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTpICAST> metric 0 id 305 =
(sh), uid 0: exited on signal 11 (core dumped)
mtu 1500
options=3D8209b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,W=
OL_MAGIC,LINKSTATE>
ether 98:90:96:d6:c9:6d
inet 172.16.8.10 netmask 0xffffff00 pid 310 (sh), uid 0: exited on =
signal 11 (core dumped)
broadcast 172.16.8.255=20
nd6 options=3D29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
media: Ethernet autoselect (none)
status: no re0: link state changed to UP
carrier
Segmentation fault (core dumped)
Startpid 314 (sh), uid 0: exited on signal 11 (core dumped)
ing devd.
Segmentation fault (core dumped)
Segmentation fault (core dumped)
Segmentation fault (core dumped)
pid 319 (sh), uid 0: exited on signal 11 (core dumped)
Segmentation fault (core dumped)
pid 330 (sh), uid 0: exited on signal 11 (core dumped)
Segmentation fault (core dumped)ubt0 on uhub2
ubt0: <Broadcom Corp BCM43142A0, rev 2.00/1.12, addr 3> on usbus0
random: harvesting attach, 8 bytes (4 bits) from ubt0
pid 339 (sh), uid 0: exited on signal 11 (core dumped)
Segmentation fault (core dumped)
pid 343 (sh), uid 0: exited on signal 11 (core dumped)
Segmentation fault (core dumped)WARNING: attempt to domain_add(bluetooth) a=
fter domainfinalize()
WARNING: attempt to domain_add(netgraph) after domainfinalize()
add host 127.0.0.1: gateway lo0 fib 0: route already in table
add net default: gateway 172.16.8.1
add host ::1: gateway lo0 fib 0: route already in table
add net fe80::: gateway ::1
add net ff02::: gateway ::1
add net ::ffff:0.0.0.0: gateway ::1
add net ::0.0.0.0: gateway ::1
Creating and/or trimming log files.
Starting syslogd.
Starting rpcbind.
NFS access cache time=3D60
No core dumps found.
Setting NIS domain: lmdhw.com.
Starting ypbind.
Clearing /tmp (X related).
Starting mountd.
NFSv4 is disabled
Starting nfsd.
Starting statd.
Starting lockd.
Recovering vi editor sessions:.
Starting lpd.
Upda
FreeBSD/amd64 (freebeast.catwhisker.org) (ttyu0)
login:=20
[end of console output -- dhw]
So ... looks as if we still have at least one issue, and we have a way
to evade the segfaults.
Bisection time? Or if there's another approach (or even a suggestion
for a revision to try first), I'm up for it. 9And yes, I'll just
be rebuilding the kernel for the rest of this exercise, I think.
That should speed things up significantly.)
Peace,
david
--=20
David H. Wolfskill david@catwhisker.org
If we wish to eliminate sources of Fake News, start at the top: D. Trump.
See http://www.catwhisker.org/~david/publickey.gpg for my public key.
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